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View Full Version : AR Trigger Group Safety Check (Just do it!)


1911su16b870
02-15-2012, 7:28 PM
For your new installs or if you change/mod your fire control group.

Well I've heard it was possible, but it finally happened to me...I received an out of specification trigger contained in a new lower parts kit.

The only way I was able to observe this was the lack of movement in the disconnector when the trigger was assembled in the lower.

So for you new builders remember to perform the Selector Test on your lowers:

1. While supporting your hammer with your off-hand, depress your trigger, the hammer should move forward. Hold the trigger back
2. While holding the trigger back, move the hammer back onto the disconnector, it should be held in place by the disconnector
3. While supporting your hammer with your off-hand, rotate the selector to safe

PASS- Hammer resets on the trigger
FAIL - Hammer drops

In my case, the trigger pocket was too narrow and would lock up the disconnector thereby disabling it. The result was the hammer fell after releasing the trigger or when rotating the selector to safe.

GettoPhilosopher
02-15-2012, 10:49 PM
For your new installs or if you change/mod your fire control group.

Well I've heard it was possible, but it finally happened to me...I received an out of specification trigger contained in a new lower parts kit.

The only way I was able to observe this was the lack of movement in the disconnector when the trigger was assembled in the lower.

So for you new builders remember to perform the Selector Test on your lowers:

1. While supporting your hammer with your off-hand, depress your trigger, the hammer should move forward. Hold the trigger back
2. While holding the trigger back, move the hammer back onto the disconnector, it should be held in place by the disconnector
3. While supporting your hammer with your off-hand, rotate the selector to safe

PASS- Hammer resets on the trigger
FAIL - Hammer drops

In my case, the trigger pocket was too narrow and would lock up the disconnector thereby disabling it. The result was the hammer fell after releasing the trigger or when rotating the selector to safe.

Friend of mine had a weirder one....disconnector wore out slightly. It wasn't worn all the way, but just enough that if he was light in releasing the trigger, the hammer would drop. If he mashed the trigger down and let it go crisp, it was fine, but when he'd take his time and ease off the trigger carefully, it'd drop and he'd get a double fire.

Poor guy thought he was inadvertently bumpfiring till the danged thing did a three round burst...he freaked out, unloaded, took off his upper, took out the trigger parts at the range, took the gun home, and threw away the FCG. ;D

mod1217
02-15-2012, 11:00 PM
Wow I never did this type of test with my selector switch thank you for the Info would be doing this tommorow

Sgt. J Beezy
02-15-2012, 11:06 PM
Which LPK was it?

Therunningidiot
02-16-2012, 5:52 AM
Just checked, my lower passed. Thanks for the info!

digitalelf
02-16-2012, 8:16 AM
I've read that the Geissele triggers do this, and no-one, not even Bill Geissele himself has said that this is a problem (that I have seen anyway)...

And Geissele triggers are supposed to be some of the best in the industry...

SmellOfCordite
02-16-2012, 10:51 AM
I've read that the Geissele triggers do this, and no-one, not even Bill Geissele himself has said that this is a problem (that I have seen anyway)...

And Geissele triggers are supposed to be some of the best in the industry...

Where did you hear this? I would like to see some solid proof that this happens because then all of my triggers would potentially be faulty. Bill never said anything about this at SHOT when I talked to him...

digitalelf
02-16-2012, 4:48 PM
Where did you hear this? I would like to see some solid proof that this happens because then all of my triggers would potentially be faulty. Bill never said anything about this at SHOT when I talked to him...

I think you misread me. I said that I have never heard him comment on this issue, meaning that if this were an issue, he WOULD have said something either way...

As for where I've "heard" that his triggers fire when held down while simultaneously removing the weapon from safe, I've read that from various posts here on Calguns...

smalltime
02-16-2012, 5:19 PM
I have an SD-E and if you move to safe with the trigger held back and disconnector engaged it will force the trigger forward until the disconnector lets go but the hammer does not fall. Safety came from a DPMS LPK.

Bug Splat
02-16-2012, 5:30 PM
I've had my share of 3 round bursts while adjusting my JP triggers when I first installed them. Passed the function tests fine at home but under recoil it knocked that hammer off the sear. Now I only load 2 rounds into my mag after adjusting my trigger. If I can fire 20 rounds without a double burst I call it good and load the mags up all the way.

ott1
02-16-2012, 6:43 PM
I've read that the Geissele triggers do this, and no-one, not even Bill Geissele himself has said that this is a problem (that I have seen anyway)...

And Geissele triggers are supposed to be some of the best in the industry...

My Geissele trigger doesn't do this and passes the safety check.

SVenigma
05-25-2012, 7:19 PM
I realize this is an older thread, but I have a question relating to the selector operation:
I am building my first AR and my lower build passed the safety check mentioned by the op. However, the selector will not rotate back to 'Safe' after releasing the hammer forward. If I recock the hammer, the selector will switch no problem. I don't yet have a BCG, so this is happening with no upper receiver or BCG installed. Is this normal that I can't leave the rifle uncocked and 'safe' or does having the upper and BCG attatched make a difference?
It is a PSA LPK in an Aero Precision lower.

fiddynut
05-25-2012, 7:39 PM
I'm not sure what's the norm. My stag lower safety select only goes to fire when the hammer is cocked but my New frontier lower will cycle both ways. I've yet to fire the new frontier lower. I think I'm scared.
BTW both lowers pass the test.

Revolver Ocelot
05-25-2012, 7:57 PM
Selector should not move unless the hammer is locked back.

1911su16b870
05-25-2012, 8:04 PM
Hammer down = Selector on Fire

This is as it should be and Eugene (http://en.wikipedia.org/wiki/Eugene_Stoner) smiles upon it :D

FX-05 Xiuhcoatl
05-25-2012, 8:27 PM
Good info, I'll be doing this test right now, well after I logout from calguns